The present invention relates to a device for producing quick couplings for dental prostheses.
Removable dental prostheses are currently known which have appropriate couplings for rapid anchoring to the remaining dental structures. Conventional couplings often have grip problems and tend to slacken in the course of time, creating many problems to their users. Furthermore, said couplings are often relatively expensive, so that their replacement is scarcely convenient.
In order to obviate this problem, a quick coupling for dental prostheses has been proposed which is capable of assuring durable grip, as described in U.S. Pat. No. 5,030,094.
Said quick coupling for dental prostheses essentially comprises at least one spherical male element, which is intended to be integrated in a fixed part of the prosthesis, and a female element, whose shape is complementary to the shape of said male element, correspondingly provided on a removable part of the prosthesis. The female element, which is intended to couple to said male element, is shaped like a cap made of plastic material which is intended to be accommodated and stably retained in the removable part of the prosthesis.
Conveniently, the seat for said plastic cap, in the removable part of the prosthesis, is defined in a metallic piece which is intended to be monolithic with said removable part. Said metallic piece is preferably obtained by lost-wax casting starting from a refractory-lined model of the arch to be reconstructed.
The male element, which is monolithic with the fixed part of the prosthesis, is instead obtained by casting starting from a corresponding prefabricated male element made of calcinable plastic material.
In practice, in order to produce the quick coupling, a metallic element, having the same outside contour as said plastic cap, is applied on the male element. The impression of the unit thus formed is then made, and a model made of refractory material is then produced and subsequently modeled in wax according to the required shape of said metallic piece which is intended to define the seat of the plastic cap. The metallic portion of the removable part of the prosthesis is finally produced by lost-wax casting.
This productive solution is quite obviously rather complicated and expensive, in terms of both work time and materials, since in practice it requires the execution of a duplicate, made of refractory material, of the piece to be modeled.